ext2fs now extremely slow

[Aditya Sarawgi]

On Wed, Nov 03, 2010 at 05:43:26PM -0700, Doug Barton wrote:
> On 11/03/10 16:38, Aditya Sarawgi wrote:
> > On Wed, Nov 3, 2010 at 5:21 AM, Doug Barton<dougb at freebsd.org>  wrote:
> 
> >> Is anything happening with this?  I recently built a new system that is
> >> multi-booting windows, freebsd, and ubuntu. I chose ext[23]fs for my /home
> >> partition so that I could share unix'y stuff between freebsd and linux, but
> >> I'm having both performance and stability problems, and today (fortunately
> >> for the first time, and fortunately recoverable) I had actual data loss. I'm
> >> happy to be a guinea pig for new code if people are reasonably sure that it
> >> will help, but if the situation doesn't improve I will have to reformat.
> >>
> >
> > Are you suffering from these problems on CURRENT ?
> 
> Yes.
> 
> > Can you please elaborate
> > on the performance and stability issue you are facing ? Any specific scenario ?
> 
> What I did was create a fairly large (37G) /home and put all the stuff 
> I'd like to have access to from all 3 systems, like svn, my ports tree, 
> etc. I also ended up putting my obj directory there because I created my 
> /usr/local a little smaller than I should have and after installing 
> gnome I ran out of room. :)
> 
> I should also point out that this is on a brand new desktop system that 
> was donated by a FreeBSD user. It's a C2D running at 3.17G, 4G RAM, and 
> a fast 250G disk. I'm running amd64 -current. Everything disk intensive 
> (updating ports with csup, updating my svn trees, etc.) is slower on 
> this system than it was on my laptop where all the same stuff was on 
> UFS2. Bruce's message that started this thread alluded to the problems, 
> my experience has been similar.
> 
> Regarding stability, sometimes (but not always) when I'm doing the above 
> listed disk-intensive things on an otherwise idle system I've had the 
> system lock up. Not panic, not reboot, just wedge. I'm running X when 
> this happens, so I'm not 100% sure that the disk activity is the 
> culprit, but it seems very suspicious. Yesterday was a very bad day, I 
> had to do 3 tries to get all the way through a buildworld/kernel, mostly 
> because the last 2 crashes resulted in my /usr/src (which is actually 
> /home/svn/head) and /usr/obj (/home/obj-9) directories getting corrupted 
> respectively. Today (running r214694) has actually been quite good, 
> although I haven't tried a buildworld yet.
>

I am not sure if this is the right use case for ext2fs 
 
> > You can test Zheng's preallocation patch for ext2fs, there is a
> > serious lack of testers for that.
> 
> I would be happy to do that, but my reading of this thread last month 
> didn't produce a clear "try this version of the patch" neon sign. 
> Various people referred to suggestions, updates, etc. If someone could 
> provide a URL for the right patch to try, as well as a suggestion for 
> benchmarking methodology, I'll be glad to do so.
>

I have attached the patch. Some primitive testing like copying files, 
untaring etc and comparing with the existing ext2fs will do. If you 
are looking to do a full fledged benchmarking then I would suggest
iozone, blogbench, dbench etc. 
 
> >> On a related note, is there any way to use the journaling features of ext3fs
> >> in FreeBSD? When I boot the linux partition it's treating the fs as ext3fs,
> >> but AFAICS we only have ext2fs capabilities.
> >>
> >
> > Journaling is difficult to bring in, especially if one is planning to
> > have a BSDL version.
> 
> Ok. I can live with accessing the stuff as ext2 from FreeBSD, and I can 
> even live with a minor performance penalty. What I can't live with is 
> instability and/or data corruption; and it should go without saying that 
> our users should not have to live with that either.
>

We were planning to use gjournal but it is too tied with UFS and it wouldn't be
compatible with ext2fs journaling. Haiku seems to have journaling for ext2fs but 
that depends a lot on BFS journaling.
Bringing in journaling code is not a option over here since they have their separate
journaling layer. 
 
> 
> Thanks for the response,
> 
> Doug
> 
> -- 
> 
> 	Nothin' ever doesn't change, but nothin' changes much.
> 			-- OK Go
> 
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> 
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